1. Field of the Invention
The present invention relates to an image display device for visually observing a three-dimensional computer graphics model.
It is considered that a device, through which a user can feel as if he or she were freely moving in a virtual environment structured with three-dimensional computer graphics models, is effective if the virtual environment can be viewed from a desired position and direction. Furthermore, when a large volume of a three-dimensional object is observed, it is considered that the device is more effective if a three-dimensional computer graphics is produced for the object to allow the user to freely view the object from a desired position and direction
2. Description of the Related Art
A three-dimensional object can be observed from a predetermined position and direction by displaying a three-dimensional computer graphics model as an image projected on a two-dimensional plane. Normally, if the user determines the position and direction of a viewpoint and the position and direction on a projection plane, then a projected image can be successfully generated.
A typical conventional technology of displaying an image on a plurality of display screens (display device) is, for example, a CAVE method as disclosed by the following reference.
[Reference] Carolina Cruz-neira, Daniel J. Sandin, Thomas A. Defanti, Rovert V. Kenyon, and John C. Hart: "The Cave audiovisual experience automatic virtual environment", Communications of ACM, Vol. 35, No. 6, pp.65-72 (1992).
The CAVE refers to a category of output device for displaying virtual reality (VR), and a plurality of display devices are arranged around the user. A plurality of display devices display the virtual environment viewed from respective viewpoints of the user. Therefore, the images output to the display devices are different from each other, but represent the entire virtual environment by displaying mutually related images. However, in the CAVE, the relative positions of the display units are fixed.
A portable computer capable of measuring the physical position and direction of the device itself is described below.
[Reference] George W. Fitzmaurice, "Situated information spaces and spatially aware palmtop computers", Communications of ACM, Vo.36, No. 7, pp.39-49 (1993).
This spatially aware palmtop computers are portable computers capable of measuring the physical position and direction of the device. The information about the position and direction of the portable computer is displayed on a display device. However, there is a single display device as in a common computer.